Heat Exchanger Plate and a Plate Package

ABSTRACT

The invention refers to a heat exchanger plate ( 1 ) and a plate package for a plate heat exchanger. The heat exchanger plate extends between a primary edge zone ( 11   a ) and a secondary edge zone ( 12   a ). A centre axis (x) divides the heat exchanger plate in a primary part ( 11 ) and a secondary part ( 12 ). The heat exchanger plate includes a first end area ( 16 ), a second end area ( 17 ), and a central heat transfer area ( 18 ) therebetween. A primary porthole ( 21 ) and a secondary porthole ( 23 ) extend through the plate in the first end area and are surrounded by the respective adjoining edge area ( 25 ). The primary porthole is located on the primary part and the secondary porthole on the secondary part. A distribution area ( 26 ) extends on the first end area and has a base surface ( 27 ) extending from the primary porthole to the central heat transfer area. The base surface is inclined and located at an upper level at an upper plane in the proximity of the edge area of the primary porthole and sinks successively to a lower level in the proximity of a lower plate plane at secondary edge zone.

BACKGROUND OF THE INVENTION AND PRIOR ART

The present invention refers to a heat exchanger plate for a platepackage for a plate heat exchanger, wherein the heat exchanger plateextends between a primary edge zone and a secondary edge zone inparallel with a central extension plane, an upper plate plane and alower plate plane, wherein the central extension plane includes a centreaxis dividing the heat exchanger plate in a primary part and a secondarypart, and wherein the heat exchanger plate includes a first end area, asecond end area, a central heat transfer area, which extends between theprimary edge zone and the secondary edge zone from the first end area tothe second end area, a primary porthole and a secondary porthole, whichextend through the heat exchanger plate in the first end area and whichare surrounded by a respective adjoining edge area, wherein the primaryporthole is located on the primary part and the secondary porthole onthe secondary part, and a distribution area which extends on the firstend area and has a base surface extending from the primary porthole tothe central heat transfer area.

The invention also refers to a plate package for a plate heat exchangerincluding at least two heat exchangers plates with a plate interspacetherebetween, wherein each heat exchanger plate extends between aprimary edge zone and a secondary edge zone in parallel with a centralextension plane, an upper plate plane and a lower plate plane, whereinthe central extension plane includes a centre axis dividing the heatexchanger plate in a primary part and a secondary part, and wherein theheat exchanger plate includes a first end area, a second end area, acentral heat transfer area, which extends between the primary edge zoneand the secondary edge zone from the first end area to the second endarea, a primary porthole and a secondary porthole, which extend throughthe heat exchanger plate in the first end area and which are surroundedby a respective adjoining edge area, wherein the primary porthole islocated on the primary part and the secondary porthole on the secondarypart, and a distribution area which extends on the first end area andhas a base surface extending from the primary porthole to the centralheat transfer area.

In such plate heat exchangers, it is desirable that the main heattransfer takes place at the central heat transfer area of the plates.The distribution areas which adjoin the portholes have the function ofdistributing the media in a uniform manner to the central heat transferarea in such way that the heat transfer takes place uniformly over thewhole central heat transfer area. It is known to provide such adistribution by means of special corrugations of the distribution area.These corrugations guide the media flow in such a way that it isuniformly distributed to the central heat transfer area. A disadvantageof such known distribution patterns is that they also contribute to atoo large pressure drop over the distribution area. Such a pressure dropdeteriorates the efficiency of the plate heat exchanger and contributesto a too large heat transfer outside the central heat transfer area.

A limitation in this context is the strength of the plate heat exchangerin the distribution area. In plate heat exchangers where the heatexchanger plates are permanently joined to each other, for instance bybrazing, strong tensile stresses arise in the plate package when mediaunder high pressure is conveyed through the plate heat exchanger. Inplate heat exchangers compressed between a frame plate and a pressureplate, strong compressive stresses arise in the plate package due to thepretensioning. In order to resist such tensile stresses and compressivestresses in the distribution area, there must be a certain number ofcontact points or contact spots between adjacent heat exchanger plates.In brazed plate heat exchangers, the heat exchanger plates are joined toeach other at these points or spots. In order to resist the differentkind of stresses it is also important that these contact points arearranged substantially straight above each other, i.e. that they form anas straight as possible line through the whole plate package.

SE-B-415 928 discloses a plate heat exchanger having a number of heatexchanger plates which each extends in parallel to a central extensionplane. Each plate includes a first end area having a primary portholeand a secondary porthole, a second end area having a primary portholeand a secondary porthole, and central heat transfer area, which extendsfrom the first end area to the second end area. The portholes for theinlet and the outlet of one and the same fluid are arranged at the sameside of the plate. The central heat transfer area has a corrugation,which creates a number of passages designed in such a way that thepassages are thinner at the side of the plate where the inlet and theoutlet for the same fluid are located.

WO85/02670 discloses a plate heat exchanger having a number of heatexchangers plates which each extends in parallel to a central extensionplane. Each plate includes a first end area having a primary portholeand secondary porthole, a second end area having a primary porthole anda secondary porthole, and central heat transfer area, which extends fromthe first end area to the second end area. The portholes for the inletand the outlet for one and the same fluid are arranged at the same sideof the plate. A first distribution area extends on the first end areaand a second distribution area extends on the second end area. Thedistribution areas and the central heat transfer area have corrugationsextending in such directions that the flow resistance in the plateinterspaces between the distribution areas is smaller than the flowresistance in the plate interspaces between the central heat transferareas.

GB-A-2 054 817 discloses a plate heat exchanger having a number of heatexchanger plates, which each extends between a left edge and a rightedge in parallel to a central extension plane, an upper plate plane anda lower plate plane. The central extension plane includes a centre axisdividing the plate in a left part and a right part. The plate includes afirst end area, a second end area and a central heat transfer area,which extends between the left edge and the right edge from the firstend area to the second end area. An inlet porthole and an outletporthole extend through the plate in the first end area and aresurrounded by a respective adjoining edge area. The inlet porthole islocated on the left part and the outlet porthole on the right part. Adistribution area extends from the first end area and has a base surfacewhich appears to be parallel to the central extension plane and whichextends from the inlet porthole to the heat transfer area. On this basesurface one or several separated distribution members are attached. Thedistribution member is designed in such a-way that it is located at anupper level in the proximity of the upper plate plane in the proximityof the edge area of the inlet porthole and sinks successively to a lowerlevel in the proximity of the lower plate plane in the proximity of theleft edge.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a heat exchanger plateintended for a plate package in a plate heat exchanger and including animproved distribution area.

A further object of the present invention is to provide such a heatexchanger plate contributing to a low flow resistance in thedistribution area.

A further object of the present invention is to provide such a heatexchanger plate that contributes to a high strength for the plate heatexchanger in the distribution area.

This object is achieved by the heat exchanger plate initially defined,which is characterised in that the base surface is located at an upperlevel in the proximity of the upper plate plane in the proximity of theedge area of the primary porthole and sinks successively to a lowerlevel in the proximity of the lower plate plane in the proximity of thesecondary edge zone. By such a design of the distribution area, theplate interspace between two heat exchanger plates in the plate packagemay obtain an increasing flow area with an increasing distance from theprimary porthole forming the inlet port of the plate package. Moreprecisely, the height of the plate interspace will be relatively smallin an area close to the inlet port and increase successively in adirection towards the opposite secondary edge zone. This designcontributes to a uniform distribution of the medium which enters via theprimary porthole over the whole inlet to, i.e. the width of, the centralheat transfer area.

According to a further embodiment of the invention, the shape of thedistribution area is produced through a compression-moulding of the heatexchanger plate. In such a way, this advantageous design of thedistribution area may also be obtained in an easy manner to a low cost.No further components or elements are needed in the plate package.

According to a further embodiment of the invention, the base surfacesinks successively along a border to the central heat transfer area fromin the proximity of the primary edge zone to in the proximity of thesecondary edge zone. In such a way, the flow resistance of the medium tothe more remote parts of the distribution area may, seen from theprimary porthole where the media is intended to enter, be reduced sothat a uniform distribution of the media along the whole central heattransfer area is achieved.

According to a further embodiment of the invention, the base surfacesinks continuously from the upper level to the lower level. It is to benoted that by the expression “successively” not only such a continuoussinking of the base surface is intended but also for instance agradually sinking of the base surface in such a way that the basesurface forms a plurality of gradually lower portions which each issubstantially parallel to the central extension plane. The continuoussinking mentioned above may be obtained by a substantially plane basesurface or a somewhat curved base surface.

According to a further embodiment of the invention, the distributionarea and the base surface extend over substantially the whole first endarea.

According to a further embodiment of the invention, the distributionarea includes a number of projections and depressions, whereinsubstantially each projection extends in a respective direction runningfrom the primary porthole towards the central heat transfer area. Suchprojections will thus guide the medium flowing from the primary portholetowards the central heat transfer area. Advantageously, substantiallyeach projection may reach the upper plate plane and substantially eachdepression may reach the lower plate plane. In such a way, theprojections and depressions of adjacent heat exchanger plates in theplate package may form mutual supports to each other in the form ofpoints, lines or areas.

According to a further embodiment of the invention, substantially eachprojection has a length which is substantially shorter than the distancefrom the primary porthole to central heat transfer area along thedirection of the projection. By means of the shortening of theprojections in this way, the medium will not be confined in channelsbetween the projections but may flow freely and in such a way bedistributed in a better way over the whole distribution area.Furthermore, the flow resistance may be kept at a low level by means ofsuch short projections.

According to a further embodiment of the invention, substantially eachdepression extends substantially perpendicular to said respectivedirection of an adjacent projection. The depressions have a very smallinfluence on the flow. The depressions project, however, into theadjacent plate interspace and guide the medium that flows therein fromthe secondary part to the primary part with regard to this heatexchanger plate. Substantially each depression may then extend in arespective direction running from the secondary porthole towards thecentral heat transfer area. Also substantially each depression hasadvantageously a length which is substantially shorter than the distancefrom the secondary porthole to the central heat transfer area along thedirection of the depression.

According to a further embodiment of the invention, each projection andeach depression have two ends and two long sides, wherein substantiallyeach projection, which is located on the secondary part, with one of theends extends to one of the long sides of a depression, and whereinsubstantially each depression, which is located on the primary part,with one of the ends extends to one of the long sides of a projection.By such a location of the projections and depressions, a relatively freeflow is achieved for the media flowing through the plate package and atthe same time favourable support points are formed between adjacent heatexchanger plates. In particular, it is to be noted that the supportpoints or support lines are located in such a way that they liesubstantially straight above each other through the whole plate package.Such a support line extending substantially straight through the wholeplate package is especially advantageous for absorbing the tensilestresses arising in a plate heat exchanger where the plates arepermanently joined to each other through for instance brazing, or thecompressive stresses arising in a plate heat exchanger where the platesare pressed against each other.

According to a further embodiment of the invention, the heat exchangerplate is symmetric with regard to the centre axis in such a way thatmost of the depressions have a shape and a position corresponding to theshape and the position of a projection on the other side of the centreaxis, wherein each depression is design to abut a projection of anadjacent turned heat exchanger plate in the plate package.

The object is also achieved by the plate package initially defined,which is characterised in that the base surface is located at an upperlevel in the proximity of the upper plate plane in the proximity of theedge area of the primary porthole and sinks successively to a lowerlevel in the proximity of the lower plate plane in the proximity of thesecondary edge zone. By such a design of the distribution area, theplate interspace will have an increasing flow area with an increasingdistance from the primary porthole forming the inlet port of the platepackage. More precisely, the height of the plate interspace will berelatively small in an area close to the inlet port and increasesuccessively in a direction towards the opposite secondary edge zone. Insuch a way, a uniform distribution of the medium, which enters via theprimary porthole channel over the whole inlet to the central heattransfer area, is achieved.

Advantageous embodiments of the plate package are defined in thedependent claims 15 to 26. Advantageously, the heat exchanger plates maythen be arranged in an alternating order in such a way that the primarypart at the first end area of a first heat exchanger plate adjoins thesecondary part of an adjacent second heat exchanger plate, wherein theheight of the plate interspace decreases successively from in theproximity of the edge area of the primary porthole with regard to thefirst heat exchanger plate to in the proximity of the secondary edgezone with regard to the first heat exchanger plate. This height maydecrease continuously or gradually. Furthermore, it is to be mentionedthat the heat exchanger plates may be arranged in an alternating orderin such a way that the primary part at the first end area of a firstheat exchanger plate adjoins the secondary part of an adjacent secondheat exchanger plate, wherein substantially each depression of the firstheat exchanger plate abuts a projection of the adjacent second heatexchanger plate. The heat exchanger plates may advantageously bepermanently joined to each other.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is now to be explained more closely through adescription of various embodiments, disclosed by way of example, andwith reference to the drawings attached hereto.

FIG. 1 discloses schematically an elevation view of a plate heatexchanger according to an embodiment of the invention.

FIG. 2 discloses schematically a side view of the plate heat exchangerin FIG. 1.

FIG. 3 discloses schematically an elevation view of the heat exchangerplate of the plate heat exchanger in FIG. 1.

FIG. 4 discloses a cross-sectional view through a plate package withheat exchanger plates along the line IV-IV in FIG. 3.

FIG. 5 discloses schematically a side view of a plate heat exchangeraccording to a second embodiment of the invention.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS OF THE INVENTION

FIGS. 1 and 2 disclose schematically a plate heat exchanger according toa first embodiment of the invention. The plate heat exchanger includes anumber of heat exchanger plates 1, see FIG. 3, which are arranged besideeach other in such a way that they form a plate package 2. In the firstembodiment, the heat exchanger plates 1 in the plate package 2 arepermanently joined to each other through for instance brazing in amanner known per se. The plate heat exchanger includes a first inletport 4 and a first outlet port 5 for a first medium, and a second inletport 6 and a second outlet port 7 for a second medium.

Each heat exchanger plate 1 has in the embodiment disclosed asubstantially rectangular basic shape and extends between a primary edgezone 11 a and a secondary edge zone 12 a in parallel with a centralextension plane 13, an upper plate plane 14 and a lower plate plane 15,see FIG. 4. The central extension plane 13 includes a longitudinalcentre axis x which divides the heat exchanger plate 1 in a primary part11 and a secondary part 12. Each heat exchanger plate 1 also includes afirst end area 16, a second end area 17 and a central heat transfer area18. The central heat transfer area 18 extends between the primary edgezone 11 a and the secondary edge zone 12 a and from the first end area16 to the second end area 17.

Each heat exchanger plate also includes four portholes 21, 23, whicheach extends through the heat exchanger plate 1. These four portholes21, 23 in the heat exchanger plates 1 in the plate package 2 form theabove mentioned inlet and outlet ports 4-7. The portholes 21, 23 arelocated at the two end areas 16 and 17, and form a primary porthole 21on the primary part 11 of each of the first and second end areas 16, 17,and a secondary porthole 23 on the secondary part 12 of each of thefirst and second end areas 16, 17. Each porthole 21, 23 is surrounded bya respective adjoining edge area 25.

Each of the first end area 16 and the second end area 12 includesdistribution area 26, which extends over substantially the wholerespective end area 16, 17 except for the portholes 21, 23. Eachdistribution area 26 has a base surface 27, which extends oversubstantially the whole distribution area 26. The base surface 27 of thedistribution areas 26 is inclined in relation to the central extensionplane 13 and is located at an upper level in the proximity of the upperplate plane 14 in the proximity of the edge area 25 of the primaryporthole 21 and sinks successively to a lower level in the proximity ofthe lower plate plane 15 in the proximity of the secondary edge zone 12a. The base surface 27 of the distribution areas 26 also sinkssuccessively along a border to the central heat transfer area 18 from inthe proximity of the primary edge zone 11 a to in the proximity of thesecondary edge zone 12 a. In the embodiment disclosed, the base surface27 of the distribution areas 26 sinks continuously from the upper levelto the lower level. It is to be noted that the base surface 27 also maysink gradually between successively lower levels which are substantiallyparallel to the central extension plane 13.

The distribution area 26 of both the end areas 16, 17, see FIG. 3,includes also a number projections 31 which project from the basesurface 27 to substantially the upper plate plane 14, and a number ofdepressions 32, which sink from the base surface 27 to substantially thelower plate plane 15. Substantially each projection 31 extends along arespective path running from the primary porthole 21 towards the centralheat transfer area 18. Substantially each projection 31 has, at least ina central part of the distribution area 26, a length which issubstantially shorter than the distance from the primary porthole 21 tothe central heat transfer area 18 along the direction of the projection31 in question.

In a corresponding manner, substantially each depression 32 extendsalong a respective path running from the secondary porthole 23 towardsthe central heat transfer area 18. Consequently, substantially eachdepression 32 extends substantially perpendicularly to the respectivedirection of an adjacent projection 31, i.e. the directions of theprojections 31 and the depressions 32 are substantially orthogonal inthe points where these directions intersect. Also substantially eachdepression 32 has, at least in a central part of the distribution area26, a length which is substantially shorter than the di stance from thesecondary porthole 23 to the central heat transfer area 18 along thedirection of the depression 32 in question.

Substantially each projection 31 and substantially each depression 32have two ends and two long sides. The projections 31 and the depressions32 are arranged in such a way that substantially each projection 31,which is located on the secondary part 12, with one of the ends extendsto one of the long sides of the depression 32 and substantially eachdepression 32, which is located on the primary part 11, extends with oneof the ends to one of the long sides of a projection 31.

Furthermore, the heat exchanger plate 1 is symmetric with regard to thelongitudinal centre axis x in such a way that most of the depressions 32have a shape and a position which correspond to the shape and theposition of a projection 31 on the other side of the longitudinal centreaxis x. Thanks to such a symmetry and due to the fact that every secondheat exchanger plate 1 in the plate package 2 is rotated 180°, eachdepression 32 will abut a projection 31 of an adjacent heat exchangerplate 1 in the plate package 2, see FIG. 4. This symmetry also meansthat the primary porthole 21 of the first end area 16 is located on thesame side of the centre axis x as the primary porthole 21 of the secondend area 17, i.e. both the primary portholes 21 are located on theprimary part 11 and both the secondary portholes are located on thesecondary part 12.

It is to be noted that a few of the projections 33 and the depressions34 along the centre axis x deviate from this symmetry since theseprojections and depression 34, respectively, have been divided in twoshorter projections 33 and depressions 34, respectively, which from twodirections extend to a respective depression 32 and projection 31.

Substantially all heat exchanger plates 1 in the plate package 2 arethus identical. In the first embodiment, the heat exchanger plates 1 arealso permanently joined to each other by any suitable method such asbrazing. Each projection 31 is then permanently joined to a depression32 of an adjacent heat exchanger plate 1.

The heat exchanger plates 1 have been manufactured throughcompression-moulding in one step from substantially plane plates.Preferably after the compression-moulding, the portholes 21-24 have beenpunched from the heat exchanger plates 1. The distribution area 26 ofthe end areas 16, 17 has thus obtained its shape through saidcompression-moulding. In the same compression-moulding step, also thecentral heat transfer area 18 has obtained the shape disclosed with twocorrugations 36 and 37 of ridges and valleys, see FIG. 3. Thecorrugation 36 adjoins the first end area 16 and the corrugation 37adjoins the second end area 17. The corrugation 36 includes ridges andvalleys forming channels 38 extending obliquely over the central heattransfer area 18 from the secondary edge zone 12 a to the primary edgezone 11 a with an angle of inclination that is about 45° in relation tothe longitudinal centre axis x. The channels 38 have a decreasing widthin such a way that the channels 38 are wider in the proximity of thesecondary edge zone 12 a and taper successively when the channels 38approach the primary edge zone 11. In the same manner the corrugation 37includes ridges and valleys forming channels 39 extending obliquely overthe central heat transfer area from the primary edge zone 11 a to thesecondary edge zone 12 a with an angle of inclination that is about 45°in relation to the longitudinal centre axis x, i.e. about perpendicularto the direction of the channels 38. Furthermore, also the channels 39have an increasing width in such a way that the channels 39 are thinnerin the proximity of the primary edge zone 11 a and becomes successivelywider when the channels 39 approach the secondary edge zone 11.

FIG. 4 discloses a section through the plate package 2. As appear aplate interspace 40 is formed between each adjacent pair of heatexchanger plates 1. The heat exchanger plates 1 are arranged in analternating order in such a way that the primary part 11 in the firstend area of a first heat exchanger plate 1 adjoins the secondary part 12of an adjacent second heat exchanger plate 1. Consequently, the heightof the plate interspace 40 will decrease successively from the edge area25 of the primary porthole 21, 22 with regard to the first heatexchanger plate 1, or the edge area 25 of the secondary porthole 23, 24with regard to the second heat exchanger plate 1, to the secondary edgezone 12 a with regard to the first heat exchanger plate 1, or to theprimary edge zone 11 a with regard to the second heat exchanger plate 1.In the embodiment disclosed the heights of the plate interspace 40decreases continuously.

In the embodiment disclosed, one of the media will thus flow intoprimary porthole 21 of the first end area 16 to the plate interspace 40concerned and be distributed uniformly over the whole width of the plateinterspace at the transition to the central heat transfer area 18.Thanks to the tapering channels 38 and thereafter the expanding channels39 a uniformly distributed flow over the whole central heat transferarea 18 is ensured. At the second end area 17, the projections 31 of thedistribution area 26 will convey the medium to the primary porthole 21where the medium leaves the plate interspace 40.

FIG. 5 discloses a plate heat exchanger according to a secondembodiment, which differs from the first embodiment in that the heatexchanger plates 1 are pressed against each other between a frame plate50 and a pressure plate 51 by means of tie bolts 52 in a manner knownper se. The heat exchanger plates 1 have the same design as in the firstembodiment with regard to the end areas 16 and 17 and the central heattransfer area 18.

The invention is not limited to the embodiments disclosed but may bevaried and modified within the scope of the following claims.

1.-26. (canceled)
 27. A heat exchanger plate for a plate package for aplate heat exchanger, wherein the heat exchanger plate extends between aprimary edge zone and a secondary edge zone in parallel with a centralextension plane, an upper plate plane and a lower plate plane, whereinthe central extension plane includes a center axis (x) dividing the heatexchanger plate into a primary part and a secondary part, the heatexchanger plate comprising a first end area, a second end area, acentral heat transfer area, which extends between the primary edge zoneand the secondary edge zone from the first end area to the second endarea, a primary porthole and a secondary porthole, which extend throughthe heat exchanger plate in the first end area and each of which issurrounded by a respective adjoining edge area, wherein the primaryporthole is located on the primary part and the secondary porthole islocated on the secondary part, and a distribution area which extends onthe first end area and has a base surface extending from the primaryporthole to the central heat transfer area, wherein the base surface islocated at an upper level in the proximity of the upper plate plane inthe proximity of the edge area of the primary porthole and sinkssuccessively to a lower level in the proximity of the lower plate planein the proximity of the secondary edge zone.
 28. A heat exchanger plateaccording to claim 27, wherein the shape of the distribution area hasbeen produced through compression-molding of the heat exchanger plate.29. A heat exchanger plate according to claim 27, wherein the basesurface sinks successively along a border to the central heat transferarea from the proximity of the primary edge zone to the proximity of thesecondary edge zone.
 30. A heat exchanger plate according to claim 27,wherein the base surface sinks continuously from the upper level to thelower level.
 31. A heat exchanger plate according to claim 27, whereinthe distribution area and the base surface extend over substantially thewhole first end area.
 32. A heat exchanger plate according to claim 27,wherein the distribution area includes a number of projections anddepressions, and substantially each projection extends in a respectivedirection running from the primary porthole towards the central heattransfer area.
 33. A heat exchanger plate according to claim 32, whereinsubstantially each projection reaches the upper plate plane andsubstantially each depression reaches the lower plate plane.
 34. A heatexchanger plate according to claim 32, wherein substantially eachprojection has a length which is substantially shorter than the distancefrom the primary porthole to the central heat transfer area along thedirection of the projection.
 35. A heat exchanger plate according toclaim 33, wherein substantially each depression extends substantiallyperpendicularly to said respective direction of an adjacent projection.36. A heat exchanger plate according to claim 32, wherein substantiallyeach depression extends in a respective direction running from thesecondary porthole towards the central heat transfer area.
 37. A heatexchanger plate according to claim 35, wherein substantially eachdepression has a length which is substantially shorter than the distancefrom the secondary porthole to the central heat transfer area along thedirection of the depression.
 38. A heat exchanger plate according toclaim 32, wherein each projection and each depression have two ends andtwo long sides, substantially each projection, which is located on thesecondary part, with one of the ends extends to one of the long sides ofa depression and substantially each depression, which is located on theprimary part, with one of the ends extends to one of the long sides of aprojection.
 39. A heat exchanger plate according to claim 32, whereinthe heat exchanger plate is symmetrical with regard to the center axis(x) so that substantially each depression has a shape and a positioncorresponding to a shape and a position of a projection on the otherside of the center axis (x), and each depression is designed to abut aprojection of an adjacent turned heat exchanger plate in the platepackage.
 40. A plate package for a plate heat exchanger including atleast two heat exchanger plates having a plate interspace therebetween,wherein each heat exchanger plate extends between a primary edge zoneand a secondary edge zone in parallel with a central extension plane, anupper plate plane and a lower plate plane, wherein the central extensionplane includes a center axis (x) dividing each heat exchanger plate intoa primary part and a secondary part, the heat exchanger plate comprisinga first end area, a second end area, a central heat transfer area, whichextends between the primary edge zone and the secondary edge zone fromthe first end area to the second end area, a primary porthole and asecondary porthole, which extend through the heat exchanger plate in thefirst end area and each of which is surrounded by a respective adjoiningedge area, wherein the primary porthole is located on the primary partand the secondary porthole is located on the secondary part, and adistribution area which extends on the first end area and has a basesurface extending from the primary porthole to the central heat transferarea, wherein the base surface is located at an upper level in theproximity of the upper plate plane in the proximity of the edge area ofthe primary porthole and sinks successively to a lower level in theproximity of the lower plate plane in the proximity of the secondaryedge zone.
 41. A plate package according to claim 40, wherein the heatexchanger plates are arranged in alternating order so that the primarypart in the first end area of a first heat exchanger plate adjoins thesecondary part of an adjacent second heat exchanger plate, wherein theheight of the plate interspaces decreases successively from theproximity of the edge area of the primary porthole with regard to theheat exchanger plate to the proximity of the secondary edge zone withregard to the first heat exchanger plate.
 42. A plate package accordingto claim 41, wherein the height of the plate interspace decreasescontinuously.
 43. A plate package according to claim 40, wherein thedistribution area includes a number of projections and depressions,wherein substantially each projection extends in a respective directionrunning from the primary porthole towards the central heat transferarea.
 44. A plate package according to claim 43, wherein substantiallyeach projection reaches the upper plate plane and that substantiallyeach depression reaches the lower plate plane.
 45. A plate packageaccording to claim 43, wherein substantially each projection has alength which is substantially shorter than the distance from the primaryporthole to the central heat transfer area along the direction of theprojection.
 46. A plate package according to claim 43, whereinsubstantially each depression extends substantially perpendicularly tosaid respective direction of an adjacent projection.
 47. A plate packageaccording to claim 43, wherein substantially each depression extends ina respective direction running from the secondary porthole towards thecentral heat transfer area.
 48. A plate package according to claim 46,wherein substantially each depression has a length which issubstantially shorter than the distance from the primary porthole to thecentral heat transfer area along the direction of the depression.
 49. Aplate package according to claim 43, wherein each projection and eachdepression have two ends and two long sides, substantially eachprojection, which is located on the secondary part, with one of the endsextends to one of the long sides of a depression and substantially eachdepression, which is located on the primary part, with one of the endsextends to one of the long sides of a projection.
 50. A plate packageaccording to claim 43, wherein the heat exchanger plates are arranged inan alternating order so that the primary part in the first end area of afirst heat exchanger plate adjoins the secondary part of an adjacentsecond heat exchanger plate, wherein substantially each depression ofthe first heat exchanger plate abuts a projection of the adjacent secondheat exchanger plate.
 51. A plate package according to claim 40, whereinsubstantially all heat exchanger plates are identical.
 52. A platepackage according to claim 40, wherein the heat exchanger plates arepermanently joined to each other.